Aluminum is a desirable metal for use in a variety of aerospace components. Aluminum has a low density while possessing a high strength-to-weight ratio. Aluminum is also durable and malleable, the latter characteristic allowing its use in a variety of shaped components. Due to these properties, aluminum and its alloys are vital to aerospace components. Nickel is also a desirable metal for aerospace components due to its innate corrosion resistance, thermal conductivity and plating ability. In particular, aluminum and nickel are desirable metals for aerospace cooling system components. These components include cold plates, heat exchangers, coolant transfer lines as well as other components in cooling systems.
Aqueous-based coolants are desirable for use in aerospace cooling systems due to their high thermal performance, low viscosities and typically low costs. When combined with components having high aluminum surface areas, however, aqueous-based coolants present significant material compatibility challenges. Namely, current commercially-available aqueous-based coolants corrode aluminum wetted surfaces. These challenges are particularly concerning for flow-restrictive components where aluminum corrosion products can restrict or block coolant flow. While some commercially-available aqueous-based coolants perform better than others, they are not designed to be compatible with components having surface areas containing a high percentage of aluminum. The non-aerospace applications such as automobile radiators for which current coolants were designed do not contain the high levels of aluminum used in many aerospace cooling system components. As a result, current coolants do not provide adequate corrosion resistance for high aluminum surface area applications. Additionally, non-aerospace components typically contain other metals such as copper and carbon steel. Coolants selected for use with components containing copper and carbon steel normally contain additional corrosion inhibitors particularly suited to those metals. Unfortunately, these additional corrosion inhibitors can cause fouling in aerospace applications and accelerate aluminum corrosion. The problems described above also affect components containing nickel. Therefore, a need exists for providing aqueous-based coolants that adequately inhibit corrosion for aerospace components that contain high amounts of aluminum and nickel surface areas.